Interest-calculator.



J. H. P. FARRAR L A. HECKER. INTEREST CALCULATOR.

,APPLICATION FILED PEB. 24, 1910.

991,204` Patented May 2, 1911.

' INVENTORS www@ vy'n-NESSES: QLAL JOHN H. r, FARBAR ANDANTON Hncxna, or NEWARK; New Jnasnr.

' INTEREST-CALCULATOR.

Specicaton of Letters Patent.

ratenteu may a, isili.

Application filed February 24, 1910.v Serial No. 545,730.

To al? whom it my concern:

Be it known that we, JOHN H. P. FARRAR and ANTON Hncxnn, citizens of the United States, residing at Newark, in the county of Essex and State' of New Jersey, have inven ed certain new 'and useful Improvements in .nterest-Calculators; and we do hereby declare the following to be a full, clear, and exact description of the invention, suchas will enable others 4skilled in the art to which it appertains to make and .use the same, reference being had to the accompanying drawings, and to. figures of reference marked thereon, which form a part of this specification. y

This invention relates to a calculator and one particularly adapted for computing in` terest for any period of time for any amount, and at dierent rates of interest.

,The device consists of a suitable support with reversible, rotatable disks which are removably placed therein, and a finger or leaf which is detachably placed on the disks and is ruled into subdivisions or lines which register with the subdivisions or concentric lines on the disks. The finger contains the times for which interest is desired, the `principal and the interest for the times desired being radially arranged in their respective places on the disks. We also place a timeindicating slide on the support which can be easily and quickly slid into and from View. A y

The invention is illustrated in the accompanying drawing, in which- Figure 1 is a front view of the device, and Fig. 2 is a side view of the same. Fig. 3 is a face view of the time-indicating sheet.

The device comprises a support formed of a tablet 10, preferably of wood havingstrips 11 Aarranged on the back thereof, these strips being supplied withbuttons 12 of soft or resilient material to protect a desk or other furniture on which it is laid. A wire' 13 can be hinged to lie between the strips 11, when the device is used flat, and be extended to form, with the tablet, an easel, vwhen it is desired to use the device i'n an upright position. A central pivotal pin 14 projects from the face of the tablet 10 and' disks 15 are removably arranged onthe pin 14 and adapted to rotate thereon. The disks are printed,

preferably, on both sides so that more matter can be placed thereon and-have radial columns having-the principals on which interest is computed arranged in a conspicuous I place in each column, preferably at the top,

each other and radial relation with their respective principals are the amounts. repthese interest amounts making up the radial columns and adapted to be swung adjacent to the edge'16 of a leaf or linger 17, `which edge is so disposed'on the linger that it is radial and is alined with the radial columns as they are brought successivelyvadjacent to or headings that identify the principal and the time for which the interest amounts are perforated at one end to receive the pin 14 and atthe'other end to receive an outside pin 18. Thus .when the interest for 10 days on $100.00 at,5% is desired, the disk for 5% is rotated -tillthe column having $100.00 as the the edgel of the nger 17. The time-imi eating subdivisions register with the concentrically alined amounts for their re.- spective times, and by running the finger down to 10 days we find the interest in the interest column to be fourteencents. 'We have not lilled all the column of numbers, but enough to. indicate what they'would contain when complete.

We. place.a time computing slide-19 0n .the tablet 10 and preferably underthe `disks 15, the slide -having 'a suitable V1handle 20 by Iwhich it can be slid in and out. The'drisk has a slot 21 which lits over the pin 14 and limits the movement ofthe slide, the slide having an edge'to conform to the disks when the slide is in. When the slide is drawn out it brings to view columns 22 as of a calendar, these columns being preferabiy arranged one for each month and having the day of its month followed by the numbcl. of days from.the irstd'ay of the year preceding, suclras Jan 1-366 or Dee 31J6'30, these columns'not being illustrated complete, but enoughibeing shown. to indicate how enable the, number of days to be found,be tween the day of `one month to the day of accuracy. v

The device is compact and light and is well adapted for otlice work, being constructor toward thecenter when the lower part of; the disk is used. In concentric relation with it. The finger is provided with subdivisionssome month following, with quickness and?,

e d to be set up vertically or laid downat.' Y The'disks are preferably printed @nlnet-h i resentingthe interest for a specified time, l

computed. fllhe finger is removable, being principal is rotated to bring-it adjacent to ico,

they would` be arranged. This slide fue Al t) sides and since they are removable, both sides can be used, beingpre'lerably printed on the opposite sides with dit'lertait rates of interest computed on the face. le prefer to use two disks, one having, on one side, a rate at 4% and on the other side at 5%, andthe second disk has its two sides provided with a rate at (5% and 7% respectively. These dit ferent 'faces will then give the rate tor from 2% to 14%, since the different and odd rates can be easily computed from the others, for instance, and 1% can be taken from the 4% disk without any trouble. Ot course it ivill be understood that we may make disks computed at any rate, but we prefer to use them as above outlined.

llaving thus described our invention, what we claim is l. A device 'tor computing interestcomprising` a support formed of a tablet, a pin projecting 'from the Atace ot the support', an annular disk perforated in its center and adapted to be placed on the pin and rotate thereon, an outside pin projecting 'from the tace ot' the tablet beyond the j'ieriphery of the disk, a linger having a column ol ,subdi-V visions on one edge. tbe finger being pro vided with perforations. one near each end. the pertointions being so disposed that they are adapted to bring the edge `vvith the subdivisions radial with the pin on which the disk rotates, the linger being adapted to be readily removed troni the pins by being slid therel'rom, and radial columns on the disk adapted to be brought in register with the subdivisions on the edge ot the finger.

2. .L device tor con'iputing interest conijnising a support 'formed of a tablet, a pin projecting,r from the tace of the support', an annular disk perforated in its center and adapted to be placed on the pin and rotate thereon, an outside pin projecting `from the tace of the tablet beyond the periphery ol the disk, a finger having a. column otl subdivisions on one edge, the finger being provided n'ith pertovations, one near each end, the pertorations being so disposed that they are adapted to bring the edge with the subdivisions radial with the pin on which the disk rotates, the linger being adapted to be readily removed from t-he pinsI by being slid therefrom, radial columns on the disk adapted to be brought in register with the subdivisions on the edge of the linger, a slide between the disk and the support, the slide havinga Slot extending approximately halt 7ay aci'toss the same, the slot being adapted to receive the central pin and acting to limit the sliding motion of the slide on the pin. a projection on the slide for manipulating it, and columns Afor a calendar arranged on the slide and occupying substantially the unslotted portion of the strip and adapted to be placed in View when uncovered by the disk when the slide is at its outward limit ot movement.

3. A device for coniputing .interest comprising a support having a central pin projecting therefrom, an annular disk placed 'on thle pin and adapted to be removed therefronnl and arranged to rotate thereon, an outside pin on the support beyond the periphery of the disk, a finger perforated near its ends, y,the pertorations being adapted to tit over t'ie two pins, subdivisions on the disk, subdivisions on the finger, the subdivisions being dapted to be brought successively in registervtvhen the disk is rotated, a slide betu'ieentln4 disk and the support, the slide having rounded side edges to be placed in register with the edges of the disk, the slide being slotted 'for substantially one-half its width, the," slide being adapted to receive the central pitn and acting to limit the sliding motion oliy the slide onthe pin, a projection on the de for manipulating it, and columns containing material to be used in conjunction ith the matter on the linger and on the disk, the columns occupying that portion of the .lide which isnlnaivertul when the slide is sli to its outward limit of movement.

ln testimony, that. \ve claim the loregoing. we have hereunto set our hands this 19th day of February i910.

J OlrlN 1I. P. FARRAR. ANTON HECRICR. Titnesses lVM. H. CA nrlnLD, E. A. PELL.

Copies of this patent may be obtained for tive cents each, by :addressing the Commissioner of Patents. Wasnngton, D. C. 

